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R S Ratani

Publications and source records attributed to R S Ratani.

8 recordsLinked to original sources
PubMed2001

Subcutaneous whole-body radionuclide venography using Tc-99m in vivo tagged red blood cells.

PURPOSE: The accurate diagnosis of deep vein thrombosis (DVT) is essential to prevent its complications and to initiate appropriate treatment. Doppler ultrasound (DUS), contrast venography, and intravenous radionuclide venography have been used for many years to detect DVT. However, obtaining venous access in the foot for injection of contrast agent can be difficult. METHODS: The authors introduce the technique of subcutaneous radionuclide venography using Tc-99m in vivo tagged red blood cells and compare it with DUS, a widely used method. Sixty patients (120 lower extremities) underwent subcutaneous radionuclide venography and DUS. RESULTS: The concordance rate was 94% in the femoral veins and 95% in the popliteal veins. Subcutaneous radionuclide venography revealed 10 iliac vein thromboses and 2 inferior vena cava thromboses that were not detected by DUS. CONCLUSIONS: Subcutaneous radionuclide venography is a useful alternative method for detecting DVT. It is particularly valuable for evaluating DVT in the iliac veins and in the inferior vena cava.

Adult↗
PubMed1999

Electrophysical factors influencing endoscopic sphincterotomy.

BACKGROUND: Analog computer techniques were used to measure electrosurgical power during sphincterotomy in experimental models and patients. METHODS: Total energy and transient changes in power were measured during sphincterotomy of bile ducts in the livers of pigs, ampullae of humans post mortem, and during clinical sphincterotomy. The effect of waveform on hemostasis was studied in experiments on canine mesenteric arteries. RESULTS: Electrosurgical waveforms (CUT, COAG, BLEND) were measured. Halving wire contact length halved energy needed to initiate cutting. The CUT waveform rarely initiated cutting at lower power settings than the BLEND waveform. With CUT, BLEND, and COAG waveforms, approximately the same energy initiated cutting. Efficiency of cutting increased linearly with power. The COAG waveform required higher power settings than BLEND or CUT to initiate cutting (p < 0.05). Force and wire diameter influenced cutting. BLEND was more effectively hemostatic than CUT (p < 0.05). COAG was significantly more hemostatic than BLEND and CUT. Cutting efficiency during clinical sphincterotomy was poor. CONCLUSIONS: This work has practical implications. Shortening wire contact length was effective in starting a cut at suboptimal settings, whereas changing from BLEND to CUT made little difference. Increasing power setting may help if cutting does not start. BLEND stops bleeding better than CUT. COAG stops bleeding better than BLEND but cuts poorly. Cutting during clinical sphincterotomy is inefficient and can be improved.

Analog-Digital Conversion↗
PubMed1998

Pelvic bioelectrical impedance measurements to detect rectal filling.

Anorectal sensory deficits are an important cause of defecatory disorders and are also a reason for evacuatory difficulties in patients undergoing total anorectal reconstruction. A method to detect rectal filling would be beneficial in such patients. We have investigated the feasibility of detecting rectal filling in vitro and in vivo by measuring changes in pelvic impedance. In vitro, a model of the pelvis was constructed using a cylindrical plastic tank filled with an electrolyte solution (conductivity 3 mS cm(-1)). Conductive Visking tubing representing the rectum was suspended in the tank and incrementally filled with artificial faeces. An impedance meter detected changes in voltage on rectal filling when an alternating current of 2 mA was passed at eight frequencies (4.8 to 612 kHz). In vivo, changes in pelvic bioelectrical impedance upon retrograde and antegrade rectal filling with artificial faeces were evaluated in three pigs, four electrodes being implanted in the pelvis. Impedance measurements accurately detected 'rectal' volume changes in vitro (n = 10, p < 0.0001; Kruskal Wallis), but not in vivo (n = 68, p = 0.48; Kruskal Wallis). This was probably due to extreme sensitivity of the detecting device to movement, a problem that needs to be resolved before this technique could be used in man.

Animals↗
PubMed1997

Electrically stimulated smooth muscle neosphincter.

BACKGROUND: Most patients undergoing total anorectal reconstruction suffer some degree of incontinence despite the incorporation of an electrically stimulated gracilis neosphincter. As smooth muscle has the ability to maintain prolonged contraction without fatigue, the aim of this study was to assess the feasibility of developing an electrically stimulated smooth muscle neosphincter. METHODS: Electrical stimulation of the rabbit colon was performed via intramural wire electrodes using a constant voltage DC stimulator. Contractile activity was recorded by serosal strain gauges and an intraluminal pressure probe. RESULTS: Basal colonic pressure was 4-13 (median 11) cmH2O. Peak pressures generated by stimulated contractions (10 V, 1 ms, 10 Hz) ranged from 14 to 37 (median 26, n = 36) cmH2O and were significantly higher than those with spontaneous contractions (P = 0.005). During continuous stimulation contractions lasted for 45-96 (median 74) s. Intermittent stimulation using trains of electrical pulses of 1-2-min duration at 1-2-min intervals produced repeated contractions. Alternative contractions were produced when intermittent electrical stimulation was performed at two sites alternately with two pairs of electrodes more than 2.5 cm apart, producing a sustained high-pressure zone. CONCLUSION: An electrically stimulated smooth muscle neosphincter is feasible. It has potential applications in the management of faecal incontinence.

Animals↗
PubMedDate not supplied

Role of CT in left-sided acute appendicitis: case report.

We present the computed tomographic findings in a case of left-sided acute appendicitis associated with midgut malrotation, which is a rare anomaly. The inflamed appendix was visualized as a tubular, fluid-filled, enhancing structure in the left lower quadrant. The entire colon was located in the left abdomen. The presence of a superior mesenteric vein rotation sign ascertained the presence of midgut malrotation. Computed tomography is useful not only in providing accurate diagnosis of left-sided appendicitis but also in detecting associated rotational anomalies, which may require separate surgical correction.

Appendicitis↗
PubMedDate not supplied

Knot tying at flexible endoscopy.

Four new knotting techniques were developed for use at flexible endoscopy: (1) half hitches tied with knot-pusher, (2) thread-locking device, (3) self-tightening slip-knot, and (4) externally releasable knot. Remoteness from site of action, access through small-diameter orifice, and difficulty in applying lateral traction to tighten knots are problems met in knot tying at endoscopy. All four knotting techniques were studied in experiments on postmortem human stomachs and used for radio-telemetry studies and anti-reflux operations in survival studies in dogs using endoscopic sewing techniques. Half hitches tied at endoscopy with a knot-pusher were also used in human studies to treat esophageal reflux and secure pH radio-telemetry capsules for long-term measurements. Externally releasable knots were used to secure nasogastric tubes to the stomach of five patients for long-term nutrition. Knot tying is feasible at flexible endoscopy by a variety of new techniques. Endoscopically tied knots can be as secure as surgically hand-tied knots and have been used successfully in man.

Animals↗